The free radical addition of dibutyl phosphites to terminal and internal double bonds of monounsaturated amides initiated by exposure to gamma-radiation from cobalt-60 was obtained in high yields. (See "Free Radical Addition of Dialkyl Phosphites to N,N-Disubstituted Amides of Unsaturated Fatty Acids and Screening of the Products for Antimicrobial Activity" by R. R. Mod et al., which appears in the Journal of the American Oil Chemists' Society, Vol. 49, pp. 634-635 (1972) and "Phosphonated N,N-Disubstituted Fatty Amides" by R. R. Mod et al., U.S. Patent Application Ser. No. 335,860, Feb. 26, 1973 3,911,120.) now U.S. Pat. No. 3,911,120. Addition of dialkyl phosphites to unsaturated compounds containing terminal and isolated double bonds that was initiated in the presence of peroxides or ultraviolet radiation has been reported. (See "The Preparation of Dialkyl Alkylphosphonates by Addition of Dialkyl Phosphites to Olefins," by A. R. Stiles et al., which appears in the Journal of the American Chemical Society, Vol. 80, pp. 714-716 (1958); "Phosphorus Derivatives of Fatty Acids. VII. Addition of Dialkyl Phosphonates to Unsaturated Compounds," by R. Sasin, et al., which appears in the Journal of the American Chemical Society, Vol. 81, pp. 6275-6277 (1959); "Evaluation of Dialkyl 11-Phosphonoundecanoates and P,P-Dialkyl 9(10)-Phosphonostearates as Plasticizers for Vinyl Chloride Polymers," by D. W. Swern, et al., which appears in the Journal of Chemical and Engineering Data, Vol. 5, pp. 484-485 (1960)).
Attempts to initiate the reaction of dialkyl phosphites with alkyl oleates by exposure to ultraviolet radiation from a high-pressure quartz-mercury-arc lamp were unsuccessful, and the reactants were recovered unchanged. (See "Phosphorus Derivatives of Fatty Acids. VII. Addition of Dialky Phosphonates to Unsaturated Compounds," by R. Sasin, et al., which appears in the Journal of the American Chemical Society, Vol. 81, pp. 6275-6277 (1959)). This suggested that initiation of reactions of the internal double bonds of these systems by exposure to ultraviolet radiation was unlikely.